Multiple switch



MULTIPLE SWITCH Filed July 19, 1935 WITNEEE fgm 522%@ ATT NEY f 1- ik Patented Jan. 18, 1938 UNITED STATES naar PATENT GFFiCE MULTIPLE SWITCH Application July 19, 1935, Serial No. 32,262

4 Claims.

This invention relates to improvements in multiple or gang switches and more particularly to multiple switches adapted to be used in radio receiving apparatus for selectively rendering the receiving circuit responsive to several radio frequency bands.

The multiple switches most commonly employed in present day multi-range radio receivers comprise a rotatable shaft carrying one or more sets of contact plates or blades which, when the shaft is revolved are adapted to successively engage a series of spring contacts mounted upon suitable xed supports. The only factor in switches of this type tending to maintain the contact pressure between the moving and stationary contacts is the spring tension of the latter contests. In time, mechanical friction will remove suilicient material from either the Iixed or the movable contacts or both to produce a poor connection.

A poor contact is particularly objectionable during the reception of short waves in the range of 15 to 50 meters at which time a slight reduction of the switch contact pressure from normal renders the receiving set inoperative. Inasmuch as no provision is made for taking up wear between the contacts, the switches must be replaced frequently resulting in considerable expense and inconvenience to the radio receiver owner.

It is an object of my invention to provide means in multiple switches oi` the type above described for adjusting the contact pressure between the movable and fixed contacts to compensate for wear resulting from normal use oi' the switch.

A further object of my invention is the provision of a multiple switch embodying means for taking up wear between the movable and iixed contacts, which is simple in construction, inexpensive to manuiacture, and readily lends itseli` to adjustment by the set owner or radio repairman.

Other objects and advantages relate to details oi the switch structure and will appear' more fully in the following description taken in connection with the accompanying drawing in which:-

Figure 1 is a plan View partially in cross section showing an embodiment of my invention;

Figure 2 is a sectional View oi the switch taken along line 2-2 of Figure l; and

Figure 3 is a sectional View of the switch taken along line 3 3 of Figure 1.

In the drawing, the reference character 5 designates a plurality of, in this instance, three contact supporting plates of insulating material and of elliptical form, as shown more clearly in Figure 2. The contact supporting plates 5 are provided at each end with a circular aperture 6 for the reception of rods 'I upon which the plates 5 are adapted to be mounted in paralled spaced relation. 5

In order to maintain the plates 5 in proper spaced relation, tubular spacing members S surrounding the rods I are positioned between the respective plates. An indexing plate Q, the purpose of which will appear more fully later, having the same general shape as plates 5 and having apertures I in its respective ends, is also adapted to be mounted upon the rods 'I and is maintained in spaced relation with the lowermost plate by means of tubular spacing members Ii.

Positioned below the indexing plate 9 and also mounted upon the rods I, is an end plate I?. maintained in the desired spaced relation with respect to the plate 9 by means of tubular spacing members I3. The lower ends of rods 'I are 20 threaded and project through the end plate I2 and are adapted to receive mounting nuts I4. The upper ends of the rods l are threaded for the reception of standard nuts I5 whereby the contact supporting plates 5, the indexing plate 9 and the end plate I2 are securely clamped in parallel spaced relation to form a rigid structure.

The mounting nuts I4.- have a thread capacity substantially greater than a standard nut; however, only a portion of this thread capacity is utilized in the threaded engagement of the nuts with the lower ends of rods I. The remaining threaded portion of the nuts III are adapted to receive screws IG for securing the switch structure to the receiver chassis frame I1 or other 35 suitable support.

The end plate I2 is provided with a centrally located bushing I8 which also serves as a bearing adapted to receive one end of a switch shaft I9 extending in parallel relation with the rods 'I through centrally positioned openings 2G of the contact supporting plates 5. The bushing I8 may be extended through a suitable opening in the support I'I and secured in clamping engagement therewith by means oi nuts 2i threaded thereon as shown in Figure l.

The shaft I9 is provided with an end portion 22 of reduced diameter so as to form a shoulder 23 between the end portion and the main portion of the shaft. The reduced end portion 22 is journaled in an end plate 2t of substantially the same form as contact supporting plates E.

The upper threaded portions of rods 'I project beyond the uppermost contact supporting plate 5 for the purpose of supporting the end plate 24. The end plate 24 is maintained in an adjustable spaced relation with respect to the upper contact supporting plate 5 by means of coil springs positioned about the rods l, between the clamping nuts I5 and the end plate. The desired adjustment of the end plate 24 is obtained by means of adjusting nuts 25 threaded on the ends of rods T into clamping engagement with the plate. Thus, as the nuts 29 are drawn against the end plate 24, the springs 25 are compressed and the end plate is moved toward the contact supporting plates 5. The end plate 24, in its movement toward the plates 5, engages the shoulder 23 of the shaft I9 to move the latter axially with the end plate. The purpose of the axial adjustment of shaft I9 will be explained more fully in connection with the following description of the Contact arrangement of the switch.

Each Contact supporting plate 5 is provided with a series of contact lingers arranged about the circular opening 2l! and having portions thereof projecting radially into the opening. In this particular instance, two sets of contact lingers are shown, each set comprising a single Contact 2S and four contacts 29, the latter projecting a lesser distance into the opening 20 than the former. Each of the contacts 28 and 29 has a straight portion 39 adapted to be riveted or otherwise secured to one side of its respective plate 5, a V-shaped resilient portion 3| extended in a radial direction into the opening 2U and adapted to engage a movable contact to be hereinafter described, and an offset portion 32 which serves as a connecting lug for making external circuit connections.

The shaft I9 is provided with -a plurality of, in this instance, three iianged hubs 33 of insulating material which may be secured against rotation relative to the shaft by means of pins 34, The axial spacing of the hubs 33 along the shaft I9 is made to correspond to the spacing of the respective contact supporting plates 5. Each hub 33 is provided with a pair of semicircular Contact plates 35 riveted or otherwise secured to one side of the hub flange. One end of each contact plate 35 may be provided with an extension 36 which serves as a. contact arm adapted to engage the shorter contact iingers 29. The contact iingers 28 are of greater length and are adapted to engage the body portion of the semi-circular plates 35.

From the foregoing description, it is apparent that the contact pressure between the movable contact plates 35 and the respective sets of contact fingers 28 and 29 depends upon the axial adjustment of the shaft I9. The axial adjustment of the shaft I9 is effected by the adjustment of the nuts 2G which when turned to compress the springs 25, moves the end plate 24 into closer relation with the upper Contact supporting plate 5 which in turn Luges the shaft i9 downwardly and consequently brings the contact plates 35 carried by the shaft, into contact engaging relation with the protruding contact iingers 23 and 29. Thus, when the Contact surfaces of contact fingers 28 and 29 4and the contact plates 55 become worn, the Contact pressure of all the contacts may be restored simultaneously by taking up the adjusting nuts 25.

As the shaft i9 is rotated, the Contact arm 36 successively engages the contact fingers 29, whereas the contact lingers 28 are continuously in engagement with the contact plates 35. In order to obtain registration of the contact arms 36 with their respective contact iingers 29 as the sha-ft I9 is rotated from one switch setting to another, a suitable indexing mechanism is provided. This mechanism comprises a plate 9, previously referred to, having a centrally located star-shaped opening 3l so as to form alternate inwardly projecting nodes 38 and depressions 39 as illustrated in Figure 3.

The indexing plate 9 is adapted to cooperate with an indexing arm 4S preferably formed from tubular stock. The arm 4Q has a iiattened rectangular end portion 4l provided with a diametrically notched circular opening 42 for the reception of the shaft I9. The shaft I9 is provided with diametrically opposed ears 43 for registration with the notches in the opening 42 whereby the arin 49 is caused to rot-ate with the shaft.

The tubular end portion 44 of the arm 40 has diametric slots 45 extending inwardly from its free end for the reception of the plate 9. The tubular portion 44 houses aV coil spring 4G and a ball 41 which is yieldingly maintained in contact with the inner edge of the plate 9. The angular position of the arm 40 upon the shaft I9 is so arranged with respect to the position of the contact arm 36 and contacts 29 that when the latter are in alignment with the Contact arm, the ball 41 will be nested in a depression 39 on the inner edge of the plate 9. The angular spacing of the depressions 39 corresponds to the angular spacing of contacts 29 so that as the shaft I9 is rotated, the ball 4T will always be nested in a depression when the contact arm 36 is in alignment with one of the contacts 29.

In order to prevent the over-running of the contact arm 36 at either end of the series of contacts 29, the indexing plate 9 may be provided with stop pins 48 protruding on either side thereof, thereby limiting the angular movement of the arm 4D to the arc subtended by the pins. To facilitate the actuation of the switch, a. control knob 49 of well-known construction is secured to the end of the shaft I9.

Although I have shown a particular multiple switch structure, it is to be understood that the same is for the purpose of illustration, and that changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims,

I claim:

1. A multiple switch comprising a plurality of Contact supporting plates, means for supporting said plates in spaced relation, a series of contact fingers mounted upon said plates, a pair of end plates, means for supporting said end plates in spaced relation with said contact supporting plates, a shaft journaled in said end plates, a. plurality of contact members carried by said shaft, said shaft being movable axially with respect to one of said end plates and adapted to be moved by the other of said end plates for positioning said contact members in contact engaging relation with said Contact fingers, and means for adjusting the position of said movable end plate for maintaining operative contact pressure between said contact members and said Contact lingers.

2. A multiple switch comprising a pair of support rods, a plurality of contact supporting plates mounted in spaced relation upon Said rods, a. series of contact fingers mounted upon said plates, a pair of end plates mounted on said rods in spaced relation with said contact supporting plates, a shaft journaled in said end plates, a. plurality of contact members carried by said sha-ft, said shaft being movable axially with respect to one of said end plates and adapted to be moved by the other of said end plates for positioning said contact members in contact engaging relation with said contact lingers, and means for adjusting the position of said movable end plate for maintaining operative contact pressure between said contact members and said contact fingers.

3. A multiple switch comprising a pair of support rods, a plurality of contact supporting plates mounted in spaced relation upon said rods, a series of contact fingers mounted upon said plates, an end plate mounted adjacent the ends of said rods in spaced relation with said contact supporting plates, a shaft journaled in said end plates, a plurality of contact members secured to said shaft, said shaft being movable axially with respect to one of said end plates for positioning said contact members in contact engaging relation with said contact lingers, and means for adjusting the other of said end plates toward and from said contact supporting plates, said last named end plate being adapted to cooperate with said shaft for controlling the axial movement thereof.

4. A multiple switch comprising a pair of support rods, a plurality of contact supporting plates, said plates being mounted in spaced relation upon said rods, a shaft, means for rotatably supporting said shaft including an end plate, means for mountingv said end plate upon said rods in variable spaced relation with said contact supporting plates, said last named means including yielding spacing means and cooperating adjusting means for adjusting the end plate toward and from the contact supporting plates, a series of contacts mounted on said contact supporting plates, a plurality of contact members carried by said shaft adapted to wipe across the face of said contacts when the shaft is rotated, said shaft being movable axially for adjusting the contact pressure between said contact members and said contacts, said end plate being adapted to cooperate with said shaft for controlling the axial movement thereof.

LAWRENCE C. LEIGHTON. 

